Top 5 Facts: Brain surgery

Milky Way

There are around 100 billion neurones in the human brain – to illustrate just how many that is, it’s about the same number of stars that exist in our galaxy!


As well as writing the Hippocratic Oath (taken by doctors to practice medicine ethically), this ancient Greek (460BC) was also an early pioneer of brain surgery.

High demand!

Incredibly, your brain only comprises somewhere around two per cent of your body weight. However, it uses an astonishing 20 per cent of its energy.


The adult human brain weighs in the region of 1,300g (2.9lb). An elephant brain, meanwhile, weighs 6,000g (13.2lb), and a cat’s brain just 30g (approximately 0.07lb)!

It’s all in the length

Neurones in your brain and central nervous system range from 1mm to 1m (0.04in to 39.4in) in length. One of the longest stretches from the spinal cord to a muscle in the foot.